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MG MGF Technical - HGF or condensation

Mayo on the dipstick, particles of it on the upper part with a blob of at the bottom, seems to disappear after a long run but reappears after a few days. Could this be the start of a HGF (I can't decide whether I have lost any coolant recently (if I have the amount must be small) or is it condensation after the car has been standing still all week and then only doing very very short journeys at the weekend.

Thanks in advance for your advice


A prevous Ford used to display similar mayo after long term short journies and cleared up after a couple of good thrashings.

My F had a very small amount at the top of the dipstick yesterday right where the wiper would collect it. None in the filler cap. No fluid change in 21 months (other than service intervals). I have resolved to check more frequently than normal but don't want to get parnoid. However, have just checked that the AA warranty is up to date.

Sounds like condensation Nigel. Any changes in the coolant level?
Rob Bell


That's the problem, even though I have been keeping an eye on the coolant ever since I bought the car, because of the problem I had with it losing most of it's coolant on my first day of ownership (faulty coolant cap), I can't say whether I have noticed any recent loss. As it's still under warranty maybe I should take it in to get the dealer to have a look at it.


Hi Nigel
I have just had this happen to me, mayo on the dipstick at the bottom and traces of it up and down the length of the dipstick, i thought it might have been condensation so i did an oil change to confirm it. 3 or 4 days later it was back again so i changed the dreaded HG, as the car had just reached 48k i thought sooner rather than later was the best option, i suggest an oil change to confirm it before jumping to conclusions about an HGF.
Wayne d'andilly

Another cause of small amount of mayo can be a leaking inlet manifold gasket, although the latest MPi gaskets are a better design they may still cause a problem. From my own experience, small droplets of mayo are the result of condensation but spanking great tubs of the stuff is a HGF. I would suggest that there is no cause for panic just yet.

tim woolcott

Nigel, I think that a thorough investigation under warranty is a very sensible suggestion - but it doesn't sound as though you have a HGF, happily.
Rob Bell


I had exactly the same last winter.

serviced and checked over at Mike problem found

disappears over the summer ( drove to SW France )

Mayo now back again..comes back with the wet weather, but gone after a good run.
I still keep an eye on it but I'm not as worried as I was last year.

Having experienced HGF but ON A BMW!!!!! NOT AN MGF!!!! I can tell you hat you wont miss the failure the wholeof the head fills with light brown mayo, It was a B****** to clear out as I had to get the sump off and wash it all down with Jizer! and when the head was off I had to do the same. I used tons of Jizer daren't put any water near it to wash it off, so I ended up stinking of Engine cleaner and so did the garage. Engine was beautifully clean!

This thread was discussed between 11/01/2004 and 14/01/2004

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